/Engine/Source/Runtime/Engine/Classes/Engine/LocalPlayer.h
Retrieves any game-specific login options for this player if this function returns a non-empty string, the returned option or options be added passed in to the level loading and connection code. Options are in URL format, key=value, with multiple options concatenated together with an & between each key/value pair
URL Option or options for this game, Empty string otherwise
virtual [FString](API\Runtime\Core\Containers\FString) GetGameLoginOptions() const